Method and apparatus for recycling lithium-ion batteries

ABSTRACT

Cathode material from exhausted lithium ion batteries are dissolved in a solution for extracting the useful elements Co (cobalt), Ni (nickel), Al (Aluminum) and Mn (manganese) to produce active cathode materials for new batteries. The solution includes compounds of desirable materials such as cobalt, nickel, aluminum and manganese dissolved as compounds from the exhausted cathode material of spent cells. Depending on a desired proportion, or ratio, of the desired materials, raw materials are added to the solution to achieve the desired ratio of the commingled compounds for the recycled cathode material for new cells. The desired materials precipitate out of solution without extensive heating or separation of the desired materials into individual compounds or elements. The resulting active cathode material has the predetermined ratio for use in new cells, and avoids high heat typically required to separate the useful elements because the desired materials remain commingled in solution.

RELATED APPLICATIONS

This patent application is a continuation (CON) of U.S. patentapplication Ser. No. 17/412,742, filed Aug. 26, 2021, entitled “CHARGEMATERIAL FOR RECYCLED LITHIUM-ION BATTERIES,” which is acontinuation-in-part (CIP) of U.S. patent application Ser. No.16/164,952, filed Oct. 19, 2018, entitled “CHARGE MATERIAL FOR RECYCLEDLITHIUM-ION BATTERIES,” which is a continuation in part (CIP) of U.S.patent application Ser. No. 15/358,862, filed Nov. 22, 2016, now U.S.Pat. No. 10,522,884, entitled “METHOD AND APPARATUS FOR RECYCLINGLITHIUM-ION BATTERIES,” which claims the benefit of U.S. ProvisionalApplication No. 62/259,161, filed Nov. 24, 2015 entitled “METHOD ANDAPPARATUS FOR RECYCLING LITHIUM-ION BATTERIES” and which is aContinuation-in-Part (CIP) of U.S. patent application Ser. No.13/855,994, filed Apr. 3, 2013, now U.S. Pat. No. 9,834,827, entitled“METHOD AND APPARATUS FOR RECYCLING LITHIUM-ION BATTERIES,” which claimsthe benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent App. No.61/620,051, filed Apr. 4, 2012, entitled “FULL CLOSED LOOP FOR RECYCLINGLITHIUM ION BATTERIES,” all incorporated herein by reference inentirety.

BACKGROUND

For decades, portable electrical power supplies have taken the form ofbatteries that release electrical energy from an electrochemicalreaction. Various battery chemistries, such as traditional “dry cell”carbon flashlight batteries, and lead acid “wet” cells common inautomobiles have provided adequate portable electrical power. Modernelectronics, however, place significantly greater demands on thelongevity and mass of batteries. Battery power has traditionally come ata premium of the mass required for the charge material for generatingsufficient current. Conventional flashlight batteries deliver only lowcurrent. Automobile batteries for delivering an intense but brief highamperage flow to a starter motor are very dense and large. Modernelectronic devices, such as cell phones, computing devices, andautomobiles, demand substantial current delivery while being lightweightand small enough to avoid hindering the portability of the host device.

Rechargeable nickel-cadmium (NiCad) and nickel metal hydride (NiMH) hadgained popularity for rechargeable batteries for portable devices.Recently, however, advances in lithium-ion batteries (LIB s) have beensignificant such that they have become the most popular power source forportable electronics equipment, and are also growing in popularity formilitary, electric vehicle, and aerospace applications. Continuingdevelopment of personnel electronics, hybrid and electric vehicles,ensures that Li-ion batteries will continue to be increasingly indemand.

SUMMARY

Exhausted LIBs undergo a physical separation process for removing solidbattery components, such as casing and plastics, and electrodes aredissolved in a solution for extracting the useful elements Co (cobalt),Ni (nickel), Mn (manganese), and Li (lithium), from mixed cathodematerials and utilizing the recycled elements to produce activematerials for new batteries. Configurations herein are based, in part,on the observation that conventional approaches do not recycle andrecover Li-ion batteries with LiNiCoAlO₂, which is being used inautomobile application (for example Tesla™ electric vehicles).

The solution includes compounds of desirable materials such as cobalt,nickel and manganese dissolved as compounds from the exhausted cathodematerial of spent cells. Depending on a desired proportion, or ratio, ofthe desired materials, raw materials are added to the solution toachieve the desired ratio of the commingled compounds for the recycledcathode material for new cells. A strong base, such as sodium hydroxide,raises the pH such that the desired materials precipitate out ofsolution without extensive heating or separation of the desiredmaterials into individual compounds or elements. The resulting activecathode material has the predetermined ratio for use in new cells, andavoids high heat typically required to separate the useful elementsbecause the desired materials remain commingled in solution and undergoonly a change in concentration (ratio) by adding small amounts of purecharge material to achieve a target composition.

Lithium-ion batteries, like their NiCd (nickel-cadmium) and NiMH(nickel-metal hydride) predecessors, have a finite number of chargecycles. It is therefore expected that LIB s will become a significantcomponent of the solid waste stream, as numerous electric vehicles reachthe end of their lifespan. Recycling of the charge material in thelithium batteries both reduces waste volume and yields active chargematerial for new batteries.

Recycling can dramatically reduce the required lithium amount. Variouschemicals in lithium ion batteries include valuable metals such ascobalt, manganese, and nickel. Additionally, battery disposal wouldrequire that fresh metals be mined for cathode material, and mining hasa much bigger environmental impact and cost than simple recycling would.In short, recycling of lithium ion batteries not only protects theenvironment and saves energy, but also presents a lucrative outlet forbattery manufacturers by providing an inexpensive supply of activecathode material for new batteries.

Current recycling procedures for Li-ion cells are generally focused onLiCoO₂ cathode materials. Although some posted their methods to recyclemore kinds of cathode materials, all are complex and not necessarilyeconomical or practical. A simple methodology with high efficiency isproposed in order to recycle Li-ion batteries economically and withindustrial viability. The disclosed approach results in synthesis ofcathode materials (particularly valuable in Li-ion batteries) fromrecycled components. In contrast to conventional approaches, thedisclosed approach does not separate Ni, Mn, and Co out. Instead,uniform-phase precipitation is employed as starting materials tosynthesize the cathode materials as active charge material suitable fornew batteries. The analytical results showed that the recycling processis practical and has high recovery efficiency, and has commercial valueas well.

Configurations herein are based, in part, on the observation that theincreasing popularity of lithium ion cells as a source of portableelectric power will result in a corresponding increase in spentlithium-based cathode material as the deployed cells reach the end oftheir useful lifetime. While 97% of lead acid batteries are recycled,such that over 50 percent of the lead supply comes from recycledbatteries, lithium ion batteries are not yet being recycled widely.While the projected increase of lithium demand is substantial, analysisof Lithium's geological resource base shows that there is insufficientlithium available in the Earth's crust to sustain electric vehiclemanufacture in the volumes required, based solely on Li-ion batteries.Recycling can dramatically reduce the required lithium amount. Arecycling infrastructure will ease concerns that the adoption ofvehicles that use lithium-ion batteries could lead to a shortage oflithium carbonate and a dependence on countries rich in the supply ofglobal lithium reserves.

Unfortunately, conventional approaches to the above approaches sufferfrom the shortcoming that recycling approaches include high temperatureprocesses to separate the compounds of the desirable materials ofcobalt, manganese, nickel and lithium. This high-temperature processresults in breaking down the compounds for separation, but only torecombine them again for new active material. The high temperatureapproach therefore requires substantial energy, expense, and processingfor separating and recombining the desirable materials.

Accordingly, configurations herein substantially overcome the describedshortcoming of heat intensive component separation described above bygenerating a low temperature solution of the desired compounds that ismixed with small amounts of additional pure forms of the desirablematerials to achieve a target ratio of the desired active chargematerials. The desirable materials are extracted by precipitation toresult in recycled active cathode material without separating orbreaking down the compounds, allowing a lower temperature and lessexpensive process to generate the active cathode materials.

The solution includes recovering active materials from lithium ionbatteries with LiNiCoAlO₂ chemistry in a manner that can be used to makenew active materials for new lithium ion batteries. To date,conventional approaches cannot recover transition metals from LiNiCoAlO2in such a form that they can be used to make new cathode materials forLNiCoO2 or LiNiCoAlO2 batteries without using expensive organicreagents. The recovered precursor material NiCoAl(OH)₂ or NiCo(OH)₂ canbe used for making new LiNiCoAlO₂ or LiNiCoO₂ cathode materials. Thismay include adding Al(OH)₃ to the precipitated material and/or Ni, Co,or Al sulfates to the solution prior to precipitation.

In the proposed approach, it is desirable that the batteries be of asingle stream chemistry (LiNiCoAlO₂) however if there are otherchemistries present in the LiMO₂ (where M is manganese, as well as Ni,Al and Co), the manganese can be removed from solution. Ni, Co and Alcan be used to precipitate precursor and synthesize cathode materials.

The claimed approach, outlined in more detail below, defines a method ofrecycling Li ion batteries including generating a solution of aggregatebattery materials from spent cells, and precipitating impurities fromthe generated solution to result in a charge material precursor.Materials are added to adjust the solution to achieve a predeterminedratio of desirable materials based on desired chemistry of the new,recycled battery. Lithium carbonate is introduced and sintered to formcathode materials in the form of LiNi_(x)Co_(y)Al_(z)O₂. Adjusting thedesirable materials includes the addition of at least one of Ni, Co orAl, and typically the addition of desirable materials is in the form ofsalts or ions. A reductant may be employed to maintain an oxidationstate of the charge material ions in solution, and impurities may beremoved by balancing of pH, oxidation state, and electrodeposition forremoval of collateral remnants from the recycling stream such asaluminum and copper current collectors, magnesium and iron from physicalcasing and conductor materials.

In the approach disclosed below, a method of recycling Li-ion batteriestherefore includes generating a solution of aggregate battery materialsfrom spent cells, and precipitating mixtures from the generatedsolution. A recycler apparatus adjusts the solution to achieve apredetermined ratio of desirable materials, and precipitating thedesirable material in the predetermined ratio to form cathode materialfor a new battery having the predetermined ratio of the desirablematerials. It should be noted that although the methods and apparatusdisclosed herein employ Li-ion batteries as an example, the principlesare intended as illustrative and could be applied to other types ofcathode materials suited to other battery chemistries.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features will be apparent from the followingdescription of particular embodiments disclosed herein, as illustratedin the accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

FIG. 1 is a context diagram of a battery recycling environment suitablefor use with configurations herein;

FIG. 2 is a flowchart of lithium battery recycling in the environment ofFIG. 1;

FIG. 3 is a diagram of charge flow (electrons) during charging anddischarging of the batteries of FIG. 1;

FIG. 4 is a diagram of battery structure of the batteries of FIG. 1;

FIG. 5 is a diagram of recycling the cathode material in the battery ofFIG. 4;

FIG. 6 is a process flow diagram of recycling lithium-aluminum ionbatteries;

FIG. 7 is a process flow for an alternate configuration of recyclinglithium-aluminum batteries using aluminum hydroxide;

FIG. 8 is a process flow diagram for a combined recycling process forboth Ni/Mn/Co (NMC) and Ni/Co/Al (NCA) batteries for any suitable molarratio; and

FIG. 9 is a Pourbaix diagram Electrodeposition of Cu as used forimpurity removal in the process of FIG. 8.

DETAILED DESCRIPTION

Depicted below is an example method and apparatus for recyclingbatteries such as lithium ion batteries. The proposed approach is anexample and is applicable to other lithium and non-lithium batteries forrecycling spent batteries and recovering active cathode materialsuitable for use in new batteries. FIG. 1 is a context diagram of abattery recycling environment 100 suitable for use with configurationsherein. Referring to FIG. 1, in the battery recycling environment 100,electronic devices 110 such as laptops, automobiles (hybrid and pureelectric), computers, smartphones, and any other type of batterysupported equipment is suitable for use with the disclosed approach. Theelectronic devices contribute spent cells 120, having exhausted cathodematerial 122 that nonetheless includes the raw materials responsive tothe recycling approach discussed herein. A physical separation process124 dismantles the battery to form a granular mass 126 of the exhaustedbattery material including the raw materials in particulate form,usually by simply crushing and grinding the spent battery casings andcells therein.

Physical separation is applied to remove the battery cases (plastic) andelectrode materials, often via magnetic separation that draws out themagnetic steel. A recycler 130 includes physical containment of asolution 141 including the remaining granular mass 126 from the spentcharge materials, typically taking the form of a powder from theagitated (crushed) spent batteries. Additional raw materials 142 areadded to achieve a predetermined ratio of the desirable materials in thesolution 141. Following the recycling process, as discussed furtherbelow, active charge materials 134 result and are employed to form newcells 140 including the recycled cathode material 132. The new cells 140may then be employed in the various types of devices 110 thatcontributed the exhausted, spent cells 120. The recycler may include anapparatus for containing the solution 141 such that a pH adjuster ormodifier and raw materials may be added to the solution 141.

FIG. 2 is a flowchart of lithium battery recycling in the environment ofFIG. 1. Referring to FIGS. 1 and 2, the method of recycling cathodematerial 122 as disclosed herein includes generating a solution 141 fromcathode materials derived from exhausted battery cells 120, as depictedat step 200. The method combines additional raw material 142 to achievea predetermined ratio of the materials in solution 141, and is such thatthe solution temperature is maintained sufficiently low for avoidinghigh temperature process common in conventional recycling approaches.The solution 141 precipitates the precursor materials 134 by increasingthe pH of the solution 141, such that the precipitated materials 134have the predetermined ratio and having suitable proportion for use tosynthesize the cathode material 132 for the new battery cells 140. Inthe example configuration, the desirable materials include manganese(Mn), cobalt (Co), and nickel (Ni) extracted from cathode material ofbattery cells. In the solution 141, the desirable materials remainingcommingled during precipitation such that the resulting cathode material134 has the correct proportion for usage in the new cells 140.

FIG. 3 is a diagram of charge flow (electrons) during charging anddischarging of the batteries of FIG. 1. Batteries in general produce anelectron flow via an electrochemical reaction that causes an electricalcurrent from the electron flow to provide the electrical power, coupledwith a corresponding flow of ions in the battery between an anode andcathode. Referring to FIGS. 1 and 3, a lithium-ion battery (LIB) 140′generates a negative electron flow 150 to power an electrical load 152in a reversible manner (for recharge), similar to other rechargeablebatteries. During charging, a charger 170 provides a voltage source thatcauses the electron flow 151′ to reverse. Lithium ions 154 move from thenegative electrode 160 to the positive electrode 162 during discharge,and back when charging. An anode tab 161 electrically connects thenegative electrodes 160 for connection to the load 152/charger 170, anda cathode tab 163 connects the positive electrodes 162. An electrolyte168 surrounds the electrodes for facilitating ion 154 transfer. Aseparator prevents contact between the anode 160 and cathode 162 toallow ionic transfer via the electrolyte 168 so that the anode andcathode plates do not “short out” from contact. The positive electrode162 half-reaction (cathode reaction), take LiCoO₂ as an example:

LiCoO₂

Li_(1-x)CoO₂ +xLi+xe ⁻

The negative electrode 160 half-reaction is:

xLi⁺ +xe ⁻+6C

Li_(x)C₆

Overall cell reaction:

C+LiCoO₂

Li_(x)C+Li_(1-x)CoO₂

During charging, the transition metal cobalt is oxidized from Co³⁺ toCo⁴⁺, and reduced from Co⁴⁺ to Co³⁺ during discharge.

FIG. 4 is a diagram of battery structure of FIG. 1. Referring to FIGS. 3and 4, the physical structure of the cell 140 is a cylinderencapsulation of rolled sheets defining the negative electrode 160 andthe positive electrode 162.

Primary functional parts of the lithium-ion battery 140 are the anode160, cathode, 162 electrolyte 168, and separator 172. LIBs use anintercalated lithium compound as the electrode materials. The mostcommercially popular anode 160 (negative) electrode material containsgraphite, carbon and PVDF (polyvinylidene fluoride) binder, coated oncopper foil. The cathode 162 (positive) electrode contains cathodematerial, carbon, and PVDF binder, coated on aluminum foil. The cathode162 material is generally one of three kinds of materials: a layeredoxide (such as lithium cobalt or nickel oxide), a polyanion (such aslithium iron phosphate), or a spinel (such as lithium manganese oxide),and defines the cathode material 122 and recycled cathode material 132as disclosed herein. Alternatively, the disclosed approach for recyclingcathode material may be applied to other materials in various batterycomponents, such as anodic and electrolyte components. The electrolyte168 is typically a mixture of organic carbonates, generally usenon-coordinating anion salts such as lithium hexafluorophosphate(LiPF₆). The electrolyte 168 acts as an ionic path between electrodes.The outside metal casing defines the negative terminal 161′, coupled tothe anode tab 161, and the top cap 163′ connects to the cathode tab 163.A gasket 174 and bottom insulator 176 maintains electrical separationbetween the polarized components.

Conventional approaches for recycling focus on LiCoO₂ in spent LIBs.

However, with the development of lithium ion battery technologies,different cathode materials are now being used to produce lithium ionbatteries such as LiCoO₂, LiFePO4, LiMnO₂, LiNi_(x)Co_(y)Al_(z)O₂ andLiNi_(x)Mn_(y)Co_(z)O₂. It can be complex to sort out lithium ionbatteries based on the battery chemistry and conventional methods cannoteffectively recycle lithium ion batteries with mixed chemistries becausedifferent procedures are required to separate the respective compoundsfor reuse as active cathode material.

The cathode materials widely used in commercial lithium ion batteriesinclude LiCoO₂, LiMn₂O₄, LiNiO₂, LiNi_(x)Co_(y)Al_(z)O₂,LiNi_(x)Mn_(y)Co_(z)O₂ and LiFePO₄. In order to recycle lithium ionbatteries effectively, it is beneficial to consider all the variousbattery chemistries. Thus, it is beneficial to develop a simpler andenvironmentally acceptable recycling process generally applicable tovarious widely used LIBs used widely. Configurations disclosed hereinpresent an example to extract compounds including the desirable elementsof Co, Ni, Mn, and Li from mixed cathode materials and utilize therecycled materials to produce active materials for batteries. Alternatechemistries may be recycled using the methods disclosed.

FIG. 5 is a diagram of recycling the cathode material in the battery ofFIG. 4. Referring to FIGS. 1, 4 and 5, at step 1 discharged Li ionbatteries 120 are crushed/shredded. Mechanical separation processes areapplied as a pretreatment to separate the outer cases and shells and theplastic fraction, as shown at step 1 a.

The sieved cathode powder will be leached by 4-5M sulfuric acid (H₂SO₄)and 29-32% hydrogen peroxide for about 2-3 hours at 70-80° C., asdepicted at step 2. Other concentrations of sulfuric acid may also beemployed. Addition of hydrogen peroxide H₂O₂ changes not only Fe2+ toFe3+, but also other metal ions Mn, Ni, Co to 2+, thus leading toseparate iron by controlling pH of the solution in step 3. Afterfiltration, residual LiFeO4 and carbon can be separated bycentrifugation, as shown at step 2 a. Other impurities are also removedfrom the surface of the solution, as shown at step 2 b.

The metallic elements of interest are transfer to the aqueous solutionas the crushed raw cathode materials form a granular mass 126 used togenerate the solution of aggregate battery materials from the spentcells, as depicted at step 3. This includes the desirable materials ofCo (cobalt), Ni (nickel), Mn (manganese), and Li (lithium in the exampleshown; other desirable materials may be employed using the presentapproach with alternate battery chemistries. The pH is adjusted toextract iron, copper and aluminum as Fe(OH)₃, Cu(OH)₂ and Al(OH)₃. Thisinvolves adjusting the pH to a range between 3.0-7.0. Accordingly, NaOHsolution is added to adjust pH number to deposit Fe(OH)₃, Cu(OH)₂ andAl(OH)₃ which have a lower solubility constant, and keep Mn²⁺, Co²⁺,Ni²⁺ in the solution, then Fe(OH)₃, Cu(OH)2 and Al(OH)3 are separated byfiltration. It should be noted that the above processes includemaintaining the solution 141 at a temperature between 40 deg. C. and 80deg. C., thus avoiding high heat required in conventional approaches.

The pH adjustment for impurity removal generally adjusts the pH based onparticular impurities sought for removal. A pH range of around 3-5, forexample, causes iron to precipitate out of solution. Copper tends toprecipitate at a pH around 5-7. Depending on the quantity and type ofimpurities in the recycling stream, the impurity removal phase maytarget different pH ranges. Once the charge material metals (Ni, Mn, Co)have been dissolved, the pH will have been reduced to around 1-3depending on the quantity and concentration of the acid leach. Beforethe pH is raised to precipitate the NMC in a pure form, impurities canbe precipitated, optionally through addition of a reductant, discussedfurther below. In other words, while adding sodium hydroxide or otherstrong base for raising the pH, the impurities precipitate out at alower pH, followed by precipitation of NMC hydroxides at a higher pH.

The desirable materials are now dissolved in the solution 141. Based onthe predetermined target ratio of the desirable materials, the solutionis adjusted to achieve the predetermined ratio of desirable materials.In the example approach, this is a 1:1:1 combination of cobalt,manganese and nickel, although any suitable ratio could be employed.Therefore, adjusting the solution includes identifying a desired ratioof the desirable materials for use in recycled cathode materialresulting from the generated solution 141, and adding raw materials 142to achieve the desired ratio, such that the raw materials includeadditional quantities of the desirable materials and subsequently addingthe new raw materials to attain the predetermined ratio. Adding the rawmaterials includes adding additional quantities of the desirablematerials for achieving the desired ratio without separating theindividual desirable materials already in solution form, therefore themixed desirable materials (Co, Mn, Ni) do not need to be separatelydrawn or extracted as in conventional approaches, which usually involvehigh heat to break the molecular bonds of the compounds. Furthermore, inan alternate configuration, selected metallic elements can be separatedfrom the solution, which can be used to synthesize particular cathodematerials. Therefore, the pH may be adjusted to extract one or moremetal ions or other elements prior to adjusting the solution for thepredetermined ratio of desirable materials, and subsequent extract theremaining desirable materials in the predetermined ratio.

Rather, the concentration of Mn²⁺, Co²⁺, Ni²⁺ in the solution is tested,and adjusted the ratio of them to 1:1:1 or other suitable ratio withadditional CoSO₄, NiSO₄, MnSO₄. NaOH solution is added to increase thepH to around 11, usually within a range of 10.0-13, thus adjusting a pHof the solution such that the desirable materials for the new (recycled)charge materials precipitate. Ni_(1/3)Mn_(1/3)Co_(1/3)(OH)₂ orNi_(1/3)Mn_(1/3)Co_(1/3)O(OH) or a mixture thereof can be coprecipitatedsuch that the respective mole ratio is 1:1:1, as depicted at step 4.Ni_(x)Mn_(y)Co_(z)(OH)₂ or Ni_(x)Mn_(y)Co_(z)O(OH) or a mixture withdifferent ratios of x, y, and z can also be precipitated. Na₂CO₃ isadded in the solution to deposit Li₂CO₃, as depicted at step 5. Finally,the recovered Ni_(1/3)Mn_(1/3)Co_(1/3)(OH)₂ and Li₂CO₃ are sintered toproduce the cathode material.

In the example arrangement, the desirable materials include manganese(Mn), cobalt (Co), and nickel (Ni) extracted from charge material 122 ofthe spent battery cells 120, in which the desirable materials remaincommingled in the solution 141 during precipitation. Adjusting the pHincludes adding a substance, such as NaOH (sodium hydroxide, alsoreferred to as lye or caustic soda) for raising the pH such that thedesirable materials precipitate, however any suitable substance forraising the pH may be employed. The end result is that adjusting the pHincludes adding sodium hydroxide for raising the pH to permitprecipitation of the desirable materials for use as cathode precursormaterial without separately precipitating the individual compoundsdefining the desirable materials. The precipitation of the desirablematerials occurs at temperatures below 80 deg. C., avoiding high heatrequired in conventional approaches. It should be further noted that, incontrast to conventional approaches, the desirable materials remaincommingled during precipitation as a combined hydroxide (OH), (OH)₂ orcarbonate (CO₃). The addition of the additional charge materials foradjusting the ratio achieves the desired molar ratio for the resultingrecycled battery. The intermediate, or precursor form will result in alithium oxide form following sintering with lithium carbonate Li₂CO₃.

Na₂CO₃ is added in the solution to deposit Li₂CO₃ at about 40° C. Afterfiltrating, Li₂CO₃ can be recycled as the starting material to synthesisthe active cathode material LiNi_(1/3)Mn_(1/3)Co_(1/3)O₂, as shown atsteps 5 and 5 a. Therefore, the method adds back the lithium to theprecipitated desirable materials to form active cathode materialsuitable for the new battery, and precipitates the desirable material inthe predetermined ratio to form charge material for a new battery 140having the predetermined ratio of the desirable materials.

The coprecipitated materials Ni_(1/3)Mn_(1/3)Co_(1/3)(OH)₂ orNi_(1/3)Mn_(1/3)Co_(1/3)O(OH) or their mixture and recovered Li₂CO₃,with additional Li₂CO₃ in molar ratio 1.1 of Li versus M(M=Ni_(1/3)Mn_(1/3)Co_(1/3)), are mixed and grinded in mortar, asdepicted at step 6. The mixture may be reformulated by any suitableprocessing to form the active cathode material 134 for new batteries140. In the example approach, the mixture was sintered at 900 for 15hours. The reaction product may be ground into powder for subsequentdistribution and reformation into new cells 140. TheLiNi_(1/3)Mn_(1/3)Co_(1/3)O₂ is sintered by a high temperaturesolid-state method at 900° C. for 15 hours.

Battery chemistries including aluminum (Al) are becoming popular forapplications such as electric vehicles, using chemistry such asLiNiCoAlO₂. Conventional approaches for recovering active materials fromlithium ion batteries with chemistry LiNiCoAlO₂ in a manner that can beused to make new active materials for new lithium ion batteries havebeen met with several shortcomings. Conventional processes cannotrecover transition metals from LiNiCoAlO₂ in such a form that they canbe used to make new cathode materials for LNiCoO₂ or LiNiCoAlO₂batteries without using expensive organic reagents. The recoveredprecursor material NiCoAl(OH)₂ or NiCo(OH)₂ can be used for making newLiNiCoAlO₂ or LiNiCoO₂ cathode materials. This may include addingAl(OH)3 to the precipitated material and/or Ni, Co, or Al sulfates tothe solution prior to precipitation. One specific example is thatsolution of nickel and cobalt sulfates was from recycled material.Al₂(SO₄)₃.18H₂O as Al starting material was dissolved in distilledwater. Subsequently, chelating agent 5-sulfosalicylic acid was dissolvedin the solution of aluminum sulfates. Solutions of transition metalsulfates, aluminum sulfate, ammonia, and NaOH were pumped into acontinuous stirred tank reactor. Total concentration of solutions of themetal sulfates was 1.5 M or other concentrations. Concentration of thechelating agent is 0.05M-0.5M. pH was controlled 10-pH. Stirring speedwas 500-1000 rpm and the temperature was controlled in 30-60° C. Afterthe reaction, NiCoAl(OH)₂ co-precipitate was filtered, washed and dried.The metal hydroxide co-precipitate precursor was mixed with 5% excesslithium carbonate thoroughly. The mixture was at first calcined at 450°C. for 4-6 h in air, and then sintered at 750-850° C. for 15-20 h in anoxygen atmosphere or air to obtain LiNi_(x)Co_(y)Al_(z)O2 powder to formcharge material suitable for use in new batteries.

For such a recycling operation, it is desirable that the batteries be ofa single stream chemistry (LiNiCoAlO₂) however if there are otherchemistries present in the LiMO₂ (where M is manganese, as well as Ni,Al and Co), the manganese can be removed from solution. Ni, Co and Alcan be used to precipitate precursor and synthesize cathode materials.

For the recovery and synthesis of LiNiCoAlO₂ there are at least twoapproaches. FIG. 6 is a process flow diagram of recycling lithium ionbatteries. FIG. 7 is a process flow for an alternate configuration ofrecycling lithium ion batteries using aluminum hydroxide.

Referring to FIG. 6, in order to undergo the recovery process, thecathode powders must be separated from the batteries/current collectors.Physical agitation of spent cell materials is used to extract cathodematerial by leaching crushed spent battery materials in a sealed systemor containment to separate current collectors in a solution, as depictedat step 601. An example method of how this could be done is by shreddingand sizing. Then the powders can be leached into solution using acombination of sulfuric acid and hydrogen peroxide, thus leaching mayinclude forming a solution from addition of at least one of hydrogenperoxide and sulfuric acid. Impurities can be removed by adjusting a pHof the solution for removing impurities by precipitating hydroxides andfiltering. This may be performed by increasing the pH to 5-7,precipitating the respective hydroxides and filtering, as disclosed atstep 602. Aluminum hydroxide may also be removed in this step. At step603, Mn ions in the solution can also be removed by adding suitablechemicals. The concentration of ions in solution will be measured andadjusted to the desired ratio based on the industrial needs. Thisincludes adding at least one of Ni, Co and aluminum salts based on adesired composition of resulting recovered charge materials, as depictedat step 604. It may be desirable to increase the pH above 7 prior toadding Al(SO4)₃ or Al(OH)₃ or other aluminum salts to the solution.Precursor materials may then be recovered by precipitating using atleast one of sodium hydroxide or potassium hydroxide, as shown at step605. Sintering the recovered precursor materials with lithium carbonateforms active cathode material, as depicted at steps 606 and 607. Theprecipitate from step 605 can be sold to material or batterymanufacturers or can then be mixed and sintered with the lithiumcarbonate to form active LiNiCoAlO₂.

In an alternate configuration, depicted in FIG. 7, no aluminum is addedto solution and Al(OH)₃ is added to the material after precipitation,after mixing it is sintered with lithium carbonate to form the activematerial. Therefore, referring to FIG. 7, steps 701-703 proceed as theircounterparts in FIG. 6. If it is desirable to recover LiNiCoO₂ materialthe procedure follows FIG. 6 but no aluminum is added back into thesolution or precipitate. Accordingly, the process includes adding onlyNi or Co prior to precipitating the recovered charge materials at step704. The process defers addition of aluminum hydroxide (step 706) untilafter precipitation (step 705) and before sintering at step 708. Ingeneral, using the processes depicted in FIGS. 6 and 7, active chargematerial formed includes LiNixCoxAlzO₂ where x, y and z are integersdefining the composition of the resulting active charge material. Othermaterials including Cu, Al, steel, carbon, lithium carbonate, and othermaterials including transition metals can also be recovered

In an alternate arrangement, the above approaches converge to a singlestream recycling process including both Ni/Mn/Co (NMC) and Ni/Co/Al(NCA) chemistries, by recognizing the common aspects of pH changes andrecombining pure (virgin) cathode materials to form a combined precursorhaving a molar ratio based on the chemistry requirements for the new,recycled cathode materials.

FIG. 8 is a process flow diagram for a combined recycling process forboth Ni/Mn/Co and Ni/Co/Al batteries for any suitable molar ratio. Inthe approach of FIG. 8, the following benefits are achieved:

1. Both LiNi_(x)Mn_(y)Co_(z)O₂ and LiNi_(x)Co_(y)Al_(z)O₂ are cathodematerials for Li-ion batteries. These cathode materials can besynthesized in the recycling process. These recovered cathode materialshave similar performance with the virgin materials and can be used tomake new batteries.

2. In the flow chart of FIG. 8, both LiNi_(x)Mn_(y)Co_(z)O₂ withdifferent ratio of Ni, Mn and Co, and LiNi_(x)Co_(y)Al_(z)O2 withdifferent ratio of Ni, Co and Al are recovered. LiNi_(x)Mn_(y)Co_(z)O2and LiNixCoyAlzO2 can be synthesized by sintering their carbonates orhydroxides with Li₂CO₃. In our previous patent, LiNi_(x)Mn_(y)Co_(z)O2is synthesized by sintering Ni_(x)Mn_(y)Co_(z)(OH)₂ and Li₂CO₃. Itshould be noted that both the elemental composition (e.g. NMC or NCA)and the molar ratio of those elements are determined both by the molarratios following leaching, and the addition of pure raw materials to theleached solution, designated by the subscripts x, y, z specifying therespective molar ratios. Other suitable battery chemistries may beformed using the disclosed approach.

3. Based on the recycling stream, LiNi_(x)Mn_(y)Co_(z)O2 orLiNi_(x)Co_(y)Al_(z)O2 can be synthesized. If the recycling streamincludes Mn based batteries or Mn compound is added, LiNixMnyCozO2 issynthesized. If the recycling stream does not include Mn based batteriesor Mn is removed, LiNixCoyAlzO2 is synthesized.

4. For both LiNixMnyCozO2 and LiNixCoyAlzO2, impurities can be removedby increasing the pH to 5-7, precipitating their hydroxides andfiltering.

5. The carbonate and hydroxide precursor precipitates can be obtained bycontrolling their solubility in the solution.

In FIG. 8, the processing of the recycling stream for generating newcharge material for the recycled battery is shown. The method forrecycling lithium-ion batteries, comprising includes, at step 801,receiving a recycling stream of expended, discarded and/or spent lithiumion batteries, and agitating the batteries to expose the internalcomponents and charge material by physical crushing, shredding and/ordisengagement to provide surface area open to liquid exposure, asdepicted at step 802.

Physical sieving and filtering remove casing, separators and largeextraneous materials at step 803, and an acid leaching process commencedat step 804. A leached solution is formed by combining crushed batterymaterial from the lithium battery recycling stream with an acidic leachagent and hydrogen peroxide (H₂O₂) to separate cathode materials fromundissolved material, as depicted at step 804. A low pH solvent bath,leach liquor or other suitable combination immerses the agitatedmaterials of the recycling stream for dissolving the cathode materialssuch as Ni, Mn, Co and Al. The acidic leach agent may be concentrationof sulfuric acid in the range of 2-7 M (molar), and in a particulararrangement, the acidic leach agent is 4M sulfuric acid.

A particular feature of the disclosed approach is adaptability tovarious target chemistries for the recycled batteries, and sourced fromvarious unknown chemistries in the recycling stream. Design or demandspecifications determine material parameters for a recycled battery byidentifying a molar ratio and elements of cathode materialscorresponding to a charge material chemistry of a recycled battery.Battery usage as directed by a customer, for example, may be anoverriding factor, such as automotive electric or hybrid vehicle usage,portable electronic devices, etc. The identified battery chemistry,specifying particular elements and molar ratios, results in the specificelectrical characteristics of the recycled batteries produced by thedisclosed approach.

Following dissolution in the leach solution, a test or sample isemployed to determine a composition of the leach solution by identifyinga molar ratio of the ions dissolved therein, thus clarifying thepreviously unknown collective composition of the input recycling stream.Recall that all charge material has remained comingled in the leachsolution-extraction or precipitation of individual elements has not beenrequired.

Based on the determined composition, Ni, Co, Mn or Al salts in a sulfate(xSO₄) or hydroxide (xOH) form are added to the leach solution to adjustthe molar ratio of the dissolved cathode material salts in the leachsolution to correspond to the identified molar ratio for the recycledbattery. Depending on the expected battery chemistry, for example, a NMCchemistry with 1:1:1 ratio may be sought, or alternatively, a NCAchemistry with 1:2:1. Any suitable ratio and combination of chargematerials may be selected. One particular selection may be thedetermination of whether manganese (Mn) is included or whether NCAmanganese-free formulation will be employed.

Prior to adjusting the molar ratio, impurities may be precipitated fromthe leach solution by adding sodium hydroxide until the pH is in a rangebetween 5.0-7.0 for precipitating hydroxide forms of the impuritiesoutside the determined material parameters, as depicted at step 805.

The determined battery chemistry and source recycling stream results ina decision point from step 805. If the chemistry for the recycledbattery include manganese (Mn), then the cathode material salts includeNi, Mn and Co in a hydroxide form, as depicted at step 806. Otherwise,if the recycled battery is devoid of Mn, then the cathode material saltsinclude Ni, Co and Al in a hydroxide form, as shown at step 809. In thenon-Mn formulation, prior to adding raw material for adjusting the molarratio, manganese ions may be removed from the leach solution.

Following the branch at step 805, in general, sodium hydroxide is addedfor raising the pH of the leach solution to at least 10 forprecipitating and filtering metal ions of the cathode materials to forma charge material precursor by coprecipitating the Ni, Co, Mn and Alsalts remaining in the leach solution as a combined hydroxide (OH),(OH)₂ or carbonate (CO₃) having a molar ratio corresponding to theidentified molar ratio for the recycled battery, the charge precursormaterial responsive to sintering for forming active cathode materials inan oxide form following sintering with lithium carbonate (Li₂CO₃).

In either step, charge precursor material is generated by raising the pHto a range of 10-13.0 for precipitating hydroxide charge material, andmore specifically, may include raising pH by adding sodium hydroxide toincrease the pH to 11.0, as depicted at steps 807 and 810. The resultingcharge material precursor has the form NixMnyCoz(OH)2, NixMnyCozCO3,NixCoyAlz(OH)2 or NixCoyAlzCO3 where the molar ratios defined by x, y,and z are based on the determined material parameters of the recycledbattery, as depicted at steps 808 and 811.

In a more general sense, the aluminum sulfate is mixed with a chelatingagent, and the aluminum sulfate solution and nickel cobalt sulfatesolutions are added with ammonium water and sodium hydroxide to areactor. A pH monitor constantly monitors and releases additional sodiumhydroxide to maintain the pH at 10.0 or other suitable pH to result incoprecipitation of the NCA precursor.

The generalized process of FIG. 8 is intended to accommodate Al basedbattery chemistries without Mn, but may also be used for any suitableformulation by modifying the molar ratios at steps 806 or 809, asapplicable.

The charge material precursor disclosed above results in an activecathode material having improved characteristics. Particles and powders,derived from the recycling stream, include surface ions that enhancepore formation and cumulative pore volume in the resulting activecathode material.

In the recycling stream, physical agitation such as crushing andshredding results in a heterogenous mass of battery materials. Thebattery materials include not only the exhausted, spent charge material,but the physical casings, electrodes, and current collector components,along with related conduction surfaces, connectors, wires and the likewhich were part of the battery product deposited in the recyclingstream. Physical separation of extraneous battery parts has limitations,and a resulting powder or granular mass inevitably contains a smallamount of impurities such as ferrous metals, copper, and othermaterials. Typically, this quantity of impurities is less than 2%.

Further, the exhausted charge material exhibits ions on the particlesurface that differ from newly refined, virgin materials thatconventional approaches employ. Conventional approached employ newlyrefined particulate forms of materials such as Ni, Mn, Co and Al, andform active charge material using exclusively virgin materials. Incontrast, the claimed approach employs particulate forms from therecycling stream, and then supplements as needed with virgin materials.Residual surface ions in the recycled materials provide an ionicpresence that facilitates pore formation for increasing the cumulativepore volume. The pore volume allows electrolyte to contact a greatersurface area and propagate more readily around the charge material forfacilitating higher discharge rates.

Performance and manufacturing ability of Lithium-Ion batteries (LIB s)are affected by the choice of materials used within the battery. Theability to control the pore size and shape, particle size and shape,surface area and density of electrode materials is significant in theoptimization of LIB performance. LIB performance is characterized byenergy storage, also known as capacity, and current delivery, also knownas loading or power. Energy and power characteristics are defined byparticle size on the electrodes. Larger particles increase the surfacearea for maximum capacity and fine material decreases it for high power.

A high surface area reduces the diffusion distance within electrodes andhelps to facilitate ion exchange between the electrode and theelectrolyte, improving the efficiency of the electrochemical reactions.In configurations herein, ions already in the recycled materials lead toan increased pore volume over virgin materials. Ions in the surface ofthe powder or particles lead to an increased pore volume in theresulting active charge material.

Conversely, decreasing particle size lowers the presence of electrolytethat fills the voids. The volume of electrolyte within the celldetermines battery capacity. Decreasing the particle size reduces thevoids between the particles, thereby lowering the electrolyte content.Too little electrolyte reduces ionic mobility and affects performance

In configurations disclosed herein, an ability to move charge quicklyand hence, high discharge rates, are preferred over battery longevity.In typical industry standards, charge and discharge rates of a batteryare governed by C-rates. The capacity of a battery is commonly rated at1 C, meaning that a fully charged battery rated at 1 Ah should provide 1A for one hour. The C-rate therefore describes discharge rate relativeto a 1 amp per hour per battery amp/hour capacity.

The disclosed active cathode material for a lithium-ion batteryencompasses a charge material precursor resulting from a recyclingstream of crushed disposed batteries. The charge material precursor hasa ratio of charge materials based on a recycled battery chemistry andimpurities resulting from the recycling stream, As discussed above, therecycled battery chemistry defines an intended molar ratio of elementsin a resulting recycled battery, including a small (typically less than2%) of impurities which remain. Impurities typically include Al, Cu andFe.

The charge material precursor further incorporates virgin stock ofelemental compounds added to meet the ratio of charge materials. Thevirgin stock includes new elemental compounds based on a virgin form ofrefined elements corresponding to the charge materials. This addedvirgin stock adjusts the charge material percentages based on thisintended molar ratio for the finished, recycled battery product. Thecharge material precursor results from coprecipitation of a combinedsolution of the charge materials from both the recycling stream and thevirgin stock based on additions of the elemental compounds to achievethe ratio of charge materials. Any amount of virgin stock may becombined with the recycled charge materials. It should be apparent thatthe effectiveness of recycling diminishes with increased quantities ofnewly refined virgin stock. Typically, the virgin stock is between10-90% of the charge material precursor.

Since the charge materials from the recycling stream have typicallyendured a number of charging cycles, the recycling stream materials haveions resulting from previous charge cycles. The charge materialprecursor results in a cumulative pore volume based on the ions from therecycling stream. The active cathode material results from sintering thecharge material precursor with lithium carbonate or similar sinteringcompound to form the active charge material.

TABLE I Discharge Rate Metric Recycled Material Control Material 1 CmAh/g 129.6 130.9 2 C mAh/g 120.8 119.4 5 C mAh/g 76.2 40.4

Ions enter from recycled medium and tend to settle on the surface,resulting in increased pore volume. The cumulative pore volume isincreased based on ions on the surface of the particles from an agitatedmass of raw materials in the recycling stream. Increased discharge ratesresult from the recycled materials, as shown in TABLE I, particularly athigher current draws such as 5 C. In one example, the charge materialprecursor results in a charge capacity of 150-160 mAh/gm at a dischargerate of 0.1 C. The recycled materials indicates the measured chargecapacity at the respective C-rates, and the control material indicatestesting of conventional or virgin charge materials.

The charge material precursor results in a charge capacity of between129.6-150 mAh/gm for supporting a discharge rate of 1.0 C. At anopposite end of the spectrum, a charge capacity of between 76.2-120-8mAh/gm was observed for supporting a discharge rate of 5.0 C.

The same tests indicate that the charge material precursor results in acumulative pore volume of between 0.000120-0.000160 c{circumflex over( )}3/g, with some samples resulting in a cumulative pore volume of0.000163 c{circumflex over ( )}3/g. The charge material precursor isdefined by particles having an average pore diameter of between20.0-20.833 A.

In the example configurations, the recycled battery chemistry is nickel,manganese, cobalt (NMC), however other chemistries such as the Al basedcharge material above. Typical molar ratios include one of equalproportions of Ni, Mn, Co; 50% Ni, 30% Mn, 20% Co; 60% Ni, 20% Mn, 20%Co; or 80% Ni, 10% Mn, 10% Co, however any suitable ratio may beemployed.

Still further, other configurations seek to improve the purity of theresulting charge material. Impurities in the charge material thatdeviate from the prescribed battery chemistry (i.e. NMC 111, 811, 532)negatively affect the charge capacity and discharge performance.Particularly when working with recycled battery materials, byproductsand ancillary materials result from aspects such as current collectors,casing, separators, electrical contacts, and other manufactured elementsused in producing the previous generation of the functional battery arepresent in the recycling stream. In particular, aluminum and coppersheets are frequently used in cathode and anode current collectors,respectively. Manganese (Mn) and iron (Fe) are often employed in thephysical casing and construction of the previous battery, such as forelectrical contacts.

Since battery materials contain mixed oxidation state transition metalsNi²⁺, Ni³⁺, Co²⁺, Co³⁺ etc., reductive leaching has been shown toincrease the effectivity of the leach. Previous applications depictsynthesizing NixMnyCoz(OH)₂ (x+y+z=1), generally referred to as aprecursor NMC(OH)₂), from recycled batteries. Recycling processes usingan acid leach as disclosed herein takes note of the oxidation state ofthe metal ions defining the NMC charge material (Ni, Mn, Co or othermetal ions). Reductive leaching is beneficial here as well. In this casenot only does the reducing agent assist in getting the desired metalions into solution but it also affects the coprecipitation of NMC(OH)₂.Although Ni²⁺ and Co²⁺ are the steady state oxidation states in aqueoussolution, Co³⁺ can be leached into solution under certain conditions. Bymaintaining the metal ions of the charge material in a particularoxidation state, purity of the resulting precursor can achieve 99.5%purity, as expected for recycled charge material stock.

In general, a reducing agent (also called a reductant, reducer, orelectron donor) is an element or compound that loses or “donates” anelectron to an electron recipient (called the oxidizing agent, oxidant,or oxidizer) in a redox chemical reaction. The reducer's oxidation stateincreases while the oxidizer's decreases; this is expressed by sayingthat reducers “undergo oxidation” and “are oxidized” while oxidizers“undergo reduction” and “are reduced”.

In a particular example, Co³+ can be leached into solution at a rate of1 mg/hr with sulfuric acid at 25° C. Thus given a particular reducingenvironment Co²+ will leach into solution vs Co³|+. Co²+ have a 99%leaching effectivity after 1 hr at 60° C. with H₂O₂ as the reducingagent. In the examples herein, it benefits the recycling process if themetal ions are in the 2+ oxidation state, as the +3 ions willprecipitate at a different pH vs 2+ions. Since the pH window to makedesirable material can be as tight as <0.05 for a given NMC composition,the presence of 3+ ions in solution present difficulties towardsgenerating dense spherical particles with tight control of the size.

A further enhancement to the NMC recycling approach discussed aboveincludes adding a reducing agent to the leaching process to maintain theoxidation states. In the recycling stream of exhausted secondarybatteries, the method of recycling charge materials from the batteriesfor use in production of recycled batteries further includes receiving agranular mass from a recycling stream based on dismantled batteries,such that the recycling stream includes a plurality of charge materialsdefined by a battery chemistry of the dismantled batteries. Each chargematerial of the plurality of charge materials is defined by a metal(such as Ni, Mn or Co) and having an oxidation state, such that thebattery chemistry defining a ratio of the charge materials for inclusionin a recycled battery. The leach acid is added to the granular mass forreducing a pH of the leach solution to dissolve the charge materials ina leach solution, such that the leach acid selected based on anoxidation state of metal ions defining the dissolved charge materials inthe leach solution. Depending on the charge material ratios of theincoming stream and the intended recycled battery chemistry, a ratioadjustment of the charge materials may be performed for achieving apredetermined molar ratio of the charge materials in the leach solution.Once the proper charge material ratio is attained though addition ofvirgin stock, a strong base is added to the leach solution for raisingthe pH to precipitate a granular form of compounds of the chargematerials, and preferably only the charge materials, such that thegranular form defines a charge material precursor responsive tosintering to form the recycled batteries.

In the examples above, the NiMnCo(OH)2 battery precursor is made from asolution of Ni, Mn and Co generated from battery waste/scrap, where theoxidation state of Ni, Mn and Co is 2+ prior to the precipitation of thebattery precursor. Because the different oxidation states have adifferent solubility constant (ksp), Ni ions in the leaching solutionshould all be of one oxidation state, likewise the Co must all be of oneoxidation state and the same with Mn. Ideally, reaction conditions aretightly controlled in order to make dense spherical particles that arerequired for the recycled battery.

The ratio adjustment includes sampling a molar ratio of the chargematerials in the leach solution. If the molar ratio is different thanthe predetermined molar ratio for the recycled battery, additionalcharge materials may be added for achieving the predetermined molarratio of the charge materials dissolved in the leach solution. Theadditional charge materials are selected based on a compoundcorresponding to the leach acid, such as sulfate forms if the leach acidis sulfuric acid. Additional materials are typically newly sourcedvirgin forms, such as nickel sulfate, manganese sulfate or cobaltsulfate in the example shown.

A higher purity is produced when the oxidation state of each of themetal ions in the leach solution is equal to the others of the metalions in the leach solution. Since Ni³+ has a different ksp vs Ni²+, itmay not be a viable approach to make battery grade precursors usingsolutions with mixed Ni oxidation states. Similarly, since Co³+ has adifferent ksp vs Co²+, and since Mn³+ or Mn⁴+ has a different ksp vsMn²+, the purity may be compromised. Accordingly, it is preferable ifthe oxidation state of each of the metal ions defining the chargematerials is 2+, resulting from adding a reductant to the leach solutionfor achieving an oxidation state of 2+ for the charge materials in theleach solution.

In general, the reductant is selected based on a solubility constant(ksp) of the reductant in combination with the charge materials.Hydrogen peroxide has been shown to be a viable reductant in theexamples above. Other reductants include, hypophosphorous acid, sodiumhypophosphite, phosphorous acid, hydrogen sulfide, sodium bisulfide,sodium sulfide, sodium bisulfite, sodium sulfite, sodium dithionite,sodium thiosulfate, hydrazine, carbon monoxide, nitric oxide and sulfurdioxide.

Similarly, the leach acid may include at least one of sulfuric acid,nitric acid, hydrochloric acid, phosphoric acid, boric acid,hydrofluoric acid, hydrobromic acid, perchloric acid, and hydroiodicacid. For example, a sulfuric acid leach with ratio adjustment usingcorresponding sulfate forms of Ni, Mn and Co provides effective ratioadjustment.

In addition to maintaining oxidation states of the metal ions in theleach solution, the reductant may also be selected to facilitateimpurity removal. Adjustment of pH along with careful selection of thereducing agent allows precipitation of impurities while leaving thecharge material ions in solution for later precipitation, thuseffectively separating impurities from the recycled stock. Preferably,selecting the leach acid and adjusting of the pH is based on thesolubility constant for forming a spherical particle of the precipitatedcharge materials. Impurity removal may occur at different stages, butoften follows the addition of the leach acid. Adjustment of the pH ofthe leach solution is done for precipitating impurities in the leachsolution resulting from the recycling stream, while leaving the chargematerials in a solution form. There is a delicate balance to keepingcharge materials in solution while precipitating the impurities,typically iron, copper, aluminum and magnesium.

In some configurations, small amounts of magnesium stabilize the NMCcrystalline structure. Therefore, allowing small amounts of magnesium asa doping agent are actually beneficial. Ratio adjustment may includeadding a dopant having a volume less than around 1% of the chargematerial and selected based on a stability of a resulting crystallinestructure of sintered charge material. At least a portion of the dopantmay be preexisting in the leach solution based on the recycling stream,such as Mg. Mg is a common dopant for high Ni NMC. Mg sits on Li sitesin the Li layer. This prevents Li/Ni mixing. Li/Ni mixing is a keyproblem for high Ni NMC as it reduces cycling stability, ratecapability, discharge capacity, and thermal stability. Because Mg sitsin the Li layer and is not electrochemically active it acts as astructure pillar for the crystal lattice. It reduces lattice variationand enhances structural reversibility. Therefore, high Ni NMC doped withMg have been shown to have longer cycle life, higher thermal stabilityand better rate capability.

Ratio adjustment therefore includes identifying a percentage of thedopant in the leach solution and adding additional dopant based on apercentage of the preexisting dopant. Other dopants may be considered,such as Al, B, and Ta.

Another technique for impurity removal includes electrodeposition ofcopper. This includes adjusting a pH of the leach solution to a rangebetween 0-5, inserting electrodes for electrodeposition into the leachsolution, and applying a voltage between 0.5 and 2.0v to the electrodesfor electrodeposition of copper remaining in the leach solution. FIG. 9is a Pourbaix diagram of Cu as used for impurity removal. Referring toFIG. 9, a graph 900 of pH to electrical voltage are shown on axes 901and 902, respectively. Cu²+ tends to be deposited in the region denotedas 905. In the recycling sequence given above, prior to theelectrodeposition of copper, other impurities may be removed byadjusting the pH to a range between 3.0 and 6.5 for precipitatingimpurities including Fe, Al and Cu. As indicated above, a lower pH inthe range of 5-7 targets Fe, and a higher pH tends to precipitate Cu, asa complement or alternative to electrodeposition.

While the system and methods defined herein have been particularly shownand described with references to embodiments thereof, it will beunderstood by those skilled in the art that various changes in form anddetails may be made therein without departing from the scope of theinvention encompassed by the appended claims.

What is claimed is:
 1. A method of recycling batteries comprising: obtaining solid battery components from lithium ion batteries; separating charge materials from the solid battery components, the charge materials including charge material metals of one or more of Ni, Mn, and Co; leaching the charge materials to obtain a solution with a first pH of a first pH range to precipitate impurities from the solution; adding one or more metal salts to the solution, the metal salts having metal cations corresponding to the charge material metals, to adjust a relative ratio of the charge material metals in the solution to a selected ratio; and precipitating a cathode material precursor from the solution, the cathode material precursor having the selected ratio.
 2. The method of claim 1, wherein leaching the charge materials to obtain the solution includes adding one or more of an acid and a reducing agent.
 3. The method of claim 1, further comprising: precipitating the cathode material precursor as a metal hydroxide form of the charge material metals to generate precipitated metal hydroxides, and combining the precipitated metal hydroxides with a lithium salt to form a cathode material.
 4. The method of claim 3, wherein a ratio of Ni:Mn:Co in the cathode material precursor corresponds to the selected ratio of the charge material metals in the solution.
 5. The method of claim 1, wherein precipitating the cathode material precursor includes increasing a pH of the solution to a second pH of a second pH range, the second pH higher than the first pH by at least twofold.
 6. The method of claim 5 wherein the first pH range is based on an ability to precipitate impurities including one or more of iron and copper while leaving the charge material metals in solution.
 7. The method of claim 5 wherein the second pH range is based on an ability to precipitate hydroxides of the charge material metals.
 8. The method of claim 5 wherein the first pH range is between 3-5 and the second pH range is between 10 and
 13. 9. A method for obtaining electrode material precursor with a selected ratio of metals from recycled lithium ion batteries, comprising leaching electrode materials of the recycled lithium ion batteries to obtain a solution including metals, each having a respective concentration; adjusting the concentrations of the metals with additional metal salts; and raising the pH of the solution to co-precipitate the metals at the selected ratio while maintaining the solution below 80° C.
 10. The method of claim 9, wherein maintaining the solution below 80° C. includes maintaining a structure of the co-precipitated metals.
 11. The method of claim 9, wherein raising the pH of the solution to co-precipitate the metals includes maintaining the metals commingled in the solution during precipitation.
 12. A method for obtaining a cathode material with a selected ratio of metallic elements from recycled battery electrode materials, comprising: leaching the metallic elements from the recycled battery electrode materials with a solution including sulfuric acid and a reducing agent, the solution having a pH within a pH range; adjusting concentrations of the metallic elements to the selected ratio using additional quantities of the metallic elements, the additional quantities sourced from refined materials; and adjusting the pH to acidic levels for removing impurities and to basic levels to precipitate the metallic elements for the cathode material.
 13. The method of claim 12 wherein the refined materials include substantially pure metal sulfates.
 14. The method of claim 12, wherein adjusting the pH to the acidic levels includes increasing the pH of the solution to a first, acidic pH to precipitate the impurities, and wherein adjusting the pH to the basic levels includes increasing the pH of the solution to a second, basic pH.
 15. The method of claim 14, wherein increasing the pH of the solution to the second, basic pH includes increasing the pH at least two times higher than the first, acidic pH.
 16. The method of claim 15 wherein the second, basic pH is between 10.5-13.0.
 17. The method of claim 15, wherein the first, acidic pH is between 3-5 based on an amount of iron in the solution for precipitating Fe(OH)₃.
 18. The method of claim 15, wherein the first, acidic pH is less than 7 for precipitating Cu from the solution.
 19. The method of claim 15, wherein the selected ratio of metallic elements includes one or more of Ni, Mn, Co as Ni_(x)Mn_(y)Co_(z)(OH)₂ where x, y and z represent molar ratios of the respective metallic elements.
 20. The method of claim 15, wherein the pH for leaching the metallic elements is lower than the first, acidic pH. 